Means for protection against short circuits.



No. 781,931. PATENTED FEB. 7, 1905. G.E.BARRY. mums FOR PROTECTIONAGAINST SHORT 011mm.

APPLICATION FILED JULY 15, 1804.

\/\/it.17esses Inventor UNITED STATEs Patented February 7, 1905.

PATENT OFFICE.

CHARLES E. BARRY, OF SCHENECTADY, NEIV YORK, ASSIGNOR TO GEN- ERALELECTRIC COMPANY, A CORPORATION OF NEV YORK.

MEANS FOR PROTECTION AGAlNST SHORT ClRCUlTS.

SPECIFICATION forming part of Letters Patent No. 781,931, dated February'7, 1905.

Application filed July 15,1904. Serial No. 216,643.

To aZZ whom, it may concern:

Be it known that I, CHARLEs E. BARRY, a citizen of the United States,residing at Schenectady, in thecounty of Schenectady and State of NewYork, have invented certain new and useful Improvements in Means forProtection Against Short Circuits, of which the following is aspecification.

My invention relates to devices for protect- IO ing against shortcircuits, and is particularly applicable to electric-railway systems.

It sometimes happens that a short circuit occurs between acollector-shoe traveling on third rail and a truck of the car. A short I5 circuit is thus produced directly from the third rail to ground withno circuit-breaker or fuse in the connection. The only way the shortcircuit can be broken is by lifting the collector-shoe from the thirdrail, and considerable damage may be done before the motorman can dothis or realize the necessity for doing it. Also fuses orcircuit-breakers occasionally fail to work, and short circuits mayresult with damage to the apparatus before the motorman can disengagethe trolley or collector-shoe from the trolley-wire or third rail.Although the amount of current-flow in one of these short circuits issufiicient to damage the car, it frequently is insufficient to open thecircuitbreaker at the power-house in the feeder supplying that sectionof the third rail, since the feeder and the circuit-breaker connectedtherein are frequently adapted for carrying the fullload current for alarge number of cars or since 3 5 the voltage-drop in the feeder andrail limits the current to a comparatively small amount.

The object of my invention is to provide protective means against suchshort circuits; and my invention consists in providing one or moreswitches normally held closed by magnet-windings connected between thesection of the third rail and ground and controlling a circuit-breakerin the feeder supplying that section. With this arrangement if thethird- 4 5 rail section becomes grounded the current fails in themagnet-winding which normally holds the switch closed, thereby openingthe circuit of a retaining-coil of the circuit-breaker in the feedersupplying the third-rail section.

5 My invention will best be understood by reference to the accompanyingdrawing, which shows diagrammatically a portion of a railway providedwith protective devices in accordance with my invention.

In the drawing, R represents the track-rails, 5 5 and T T two sectionsof a third rail.

A represents a generator or source of power with one terminal connectedto the bus-bar a and the other terminal earthed. The bus-bar a isconnected, through the circuit-breakers B and B, to the feeders F and E,which are connected, respectively, to the third-rail sections T and T. Aplurality of coils C C are connected between the third-rail section Tand ground. Each of these coils controls a nor- 5 mall y closed switch.The several switches are placed in series in a conductor 0, whichconnects one terminal of the magnet-coil b to earth, the other terminalof this coil being connected to the bus-bar a. This coil Z) is theretaining- 7 coil for the circuit-breaker B, which may be arranged inthe manner of ordinary underload circuit-breakers.

The operation is evident from the foregoing description. If a shortcircuit occurs at any place upon the third-rail section T, the voltageacross the terminals of a coil C will fall, and the switch controlledthereby will be opened. The retaining-coil b will thereby be deenergizedand the circuit-breaker B will open, breaking the circuit of feeder Fand disconnecting the third-rail section T from the source of power.

It will be understood thatI have illustrated my inventiondiagrammatically and that many 5 modifications may be made in theconstruction and arrangement of parts without departing from the spiritof my invention. I aim in the appended claims to cover all suchmodifications. 9

\Vhat I claim as new, and desire to secure by Letters Patent of theUnited States, is-- 1. In combination, a conductor, a source of powerconnected thereto, a magnetwinding connected between said conductor andthe opposite polarity of the system, and means 0perative upon thedeenergizing of said winding for disconnecting said conductor from saidsource.

2. In combination, a conductor, a source of I00 power connected thereto,a magnet-winding connected between said conductor and theopposite'polarity of the system, a normally closed switch controlled bysaid magnet-winding, and means controlled by said switch for breakingthe connection between said conductor and said source.

3. In combination, a conductor, a source of power connected thereto, amagnet-winding connected between said conductor and the oppositepolarity of the system, a normally closed switch controlled by saidmagnet-winding, a circuit-breaker in the connection between saidconductor and the source, and a retaining-coil for said circuit-breakerin circuitwith said switch.

4. In combination, a conductor, a source of power connected thereto, aplurality of magnet-windings connected in parallel between differentpoints on said conductor and the op posite polarity of the system, andmeans operative upon the deenergizing of any one of said windings fordisconnecting said conductor from said source.

5. In combination, a conductor, a source of power connected thereto, acircuit-breaker in said connection, a retaining-coil adapted to holdsaid circuit-breaker closed, a plurality of normally closed switchesconnected in series in the circuit of said coil, and a plurality ofmagnet-windings adapted to hold said switches closed and connected inparallel between different points on said conductor and the oppositepolarity of the system.

6. In an electric-railway system, a sectional third rail, a source ofpower having one of its terminals connected to the sections of said railand its other terminal to a ground-return, magnet-windings connectedbetween the several sections and the ground-return, and normally closedswitches in the connections from the source of supply to the severalsections of the third rail controlled by said magnetwindings.

In witness whereof I have hereunto set my hand this 13th day of July,1904.

CHARLES E. BARRY.

lVitnesses:

BENJAMIN B. HULL, HELEN ORFORD.

